The Anatomy of the Cardiovascular System 1 Flashcards
Define the term ‘mediastinum’ - where it lies, where it extends from and what it contains
The mediastinum lies between the right and left pleurae.
It extends from the sternum to the vertebral column and contains all the thoracic structures except the lungs and pleura.
Describe the subdivisions of the mediastinum and give an example of a structure found in each subdivision
- Anterior mediastinum
- Superior mediastinum
- Middle mediastinum
- Posterior mediastinum
Describe the position of the heart and major blood vessels in the mediastinum/thorax
ANTERIORLY
- Sternum & costal cartilage 4-7
POSTERIORLY
- Oesophagus & descending aorta
- Vertebrae T5-T8 in recumbent position
LATERALLY
- Pleura & phrenic nerve
INFERIORLY
- Central tendon of diaphragm
Describe the tissue layers of the heart
2 PERICARDIA:
- Fibrous pericardium = dense connective tissue sac
- Serous pericardium = outer parietal layer
Inner visceral layer = Epicardium
Pericardial cavity = Between parietal and visceral layers, filled with fluid
Briefly describe the fibrous skeleton of the heart and the orientation of the heart muscle fibres around this.
Describe the major features of the coronary circulation of the heart (including its venous drainage - cardiac veins and coronary sinus)
2 CORONARY ARTERIES
- right coronary artery
- left coronary artery
3 MAIN CARDIAC VEINS
- Great cardiac vein = lies alongside anterior interventricular artery
- Middle cardiac vein = lies alongside posterior interventricular artery
- Small cardiac vein = lies alongside right marginal artery
Describe the orientation of the 4 heart chambers and the main constituents of each
Right atrium
Right ventricle
Left atrium
Left ventricle
Describe the intrinsic and extrinsic innervation of the heart
INTRINSIC
Sinoatrial node –> Atrioventricular node –> Atrioventricular bundle –> Heart wall & heart wall vessels
EXTRINSIC
Intrinsic innervation modified externally by nerves in cardiac plexus = vagus + sympathetic
Describe the borders and surfaces of the heart as seen in the anatomical position
BORDERS OF THE HEART:
- Right border = RA
- Left border = LV
- Superior border = R + L auricles + great vessels
- Inferior border = RV + LV
SURFACES OF THE HEART
- Anterior (sternocostal) surface = 1/3 RA, 2/3 RV +LV
- Inferior (diaphragmatic) surface = RV + LV
- Posterior surface (base) = LA
Describe the surface markings of the ‘apex beat’ and heart valves, including the areas for valve auscultation
HEART = lies anterior to vertebrae T5-T8
APEX = 5th LEFT intercostal space, midclavicular line = LV
What are the two main circulations of the CVS
Pulmonary
- Heart-lungs-heart
Systemic
- Heart-body-heart
Portal
- one that begins and ends in interconnected capillary beds
What are the two branches of the right coronary artery
- Right marginal artery
- Posterior interventricular artery
What are the two branches of the left coronary artery
- Left anterior descending artery
- Circumflex artery (C.A. gives off left marginal artery)
What does anastomosis occur between? And where do they occur?
- Anterior and posterior descending artery
- Circumflex + right coronary artery
on posterior surface of heart
What contains the branches of the coronary arteries?
2 major sulci
- CORONARY (atrioventricular) sulcus = between atria + ventricles
- INTERVENTRICULAR sulcus = between right and left ventricles
